Method for controlling the discharge of combustible fluid from oil wells and the like



Oct. 11, 1966 A. HOUPEURT ETAL 3277,964

METHOD FOR CONTROLLING THE DISCHARGE OF GOMBUSTIBLE FLUID FROM OIL WELLSAND THE LIKE Filed Feb. 15, 1963 3 Sheets-Sheet 1 Fig.1 a I L1. //&;.m//

INVENTORS Alva/ 5 flou sukr JEAN MOU/VLEV/IT ATTORNEYS Oct. 11, 1966 A.HOUPEURT ETAL 3,277,964 METHOD FOR CONTROLLING THE DISCHARGE OFOOMBUSTIBLE FLUID FROM OIL WELLS AND THE LIKE Filed Feb. 15, 1963 5Sheets-Sheet 2 IN YEN TOPS HNORE IL/OUPEMPT (Is/11v MWRLEVAT 5r 7 HQUPETAL THE DISCHARGE OF COMBUS FLUID FROM OIL WELLS AND THE 5 Sneet eet 3Filed "eb.

ATTO YS United States Patent METHQD FUR CUNTROLUNG THEE DHSCHARGE 0FCUMBUSTHBELE l LUil) FRUM OIL WELLS AND THE Mitt? Andre Houpeurt, 29 hisRue Chardon, Lagache, Paris, France, and Jean Mourievat, 23 Ave.Pasteur, Vain/es, France Filed lFeb. 15, 1963, Ser. No. 258,84 Claimspriority, application France, Feb. 17, W62, 888,396 4 Claims. (Cl.166-35) This invention relates to hydrocarbon-mining techniques, andmore especially to methods and means of handling accidental blowout ofcombustible liquid and gas from the head of a well or borehole.

Such blowouts not only represent a considerable loss of valuablehydrocarbon product, but are a source of atmospheric pollution as wellas a serious fire hazard. The high-pressure discharge of gas and oil isvery difficult to control and the resulting fires are equally difficultto put out. Conventional procedures for this purpose frequently involvedrilling an auxiliary hole leading to a point of the underground sheetof hydrocarbon adjacent the foot of the first hole, and dumping largeamounts of mud in an attempt to stop the discharge. Such procedures aretedious, expensive and unreliable. Moreover, when successful, extractionfrom the initial well cannot generally be resumed, with serious economicconsequences.

()bjects of the invention are to provide improved techniques andequipment for controlling the accidental discharge of combustible fluidsunder high pressures from a Well or borehole, whereby dangerous blowoutscan be arrested in a comparatively short time, reliably and relativelycheaply, and in such a manner as to allow the initial well to be putback into commission in a short time after the blowout has been dealtwith. A related object is to avoid contaminating the sheet ofhydrocarbon with mud and water. Further objects are to provide improvedcombined drill-and-injector appliances operable for first drilling ahole through a well casing pipe or the like, and then injecting materialinto said pipe through the hole thus formed.

The invention will be described with reference to the accompanyingdrawings, given by way of illustration but not of limitation andwherein:

FIG. 1 is a schematic vertical section through an oil well fitted withequipment according to the invention for controlling a blowout,

FIG. 2 is a larger-scale view, with parts broken away and shown insection, of a part of the well of FIG. 1 fitted with a tapping sleeve orshell according to the invention,

FIG. 3 is a view on a further enlarged scale, with parts broken away andshown in section, illustrating a combined drilling and injectionappliance,

H6. 4 is a section through the well casing for illustrating the pinchingoperation, and

FIG. 5 is a cross section. on line V-V of FIG. 4 after the pinchingoperation has been completed.

In accordance with the invention, for controlling blow out in anoil-well or the like, a branch pipe is connected with the casing of theWell some distance below the ground surface, and the well casing ispinched some distance above the branch connection. Referring to FIG. 1,a well is shown as bored from the surface 1 of the ground to anunderground bed 2 of oil or natural gas. The well is provided with aconventional casing pipe 3 comprising a series of sectionsinterconnected as at 4 by threaded joints or the like. An upper portionof the well usually includes, as shown, an outer casing 5 ofsubstantially ICC larger diameter than the inner casing 3 so as to bespaced coaxially around it, and cement 6 is cast in between the twocasing pipes 3 and 5.

Assuming a blowout has occurred at the well orifice a gallery 9 istunneled to connect with a point of the well at a point situated wellbelow the danger zone where a fire hazard from the blowout is present,for connection of a branch line or tap to the well casing 3 as presentlydescribed. One or more additional tunnels, two being shown at 8 and 7,are similarly made to connect with the well at respective points spaceda relatively short distance above the gallery 9. The connecting pointsof the galleries 7, 8, and 9 with the well casing are preferablyselected to lie intermediate the casing joints such as 4. Chambers suchas 7a, 8a and 9a are recessed around the well casing at the point ofconnection of the galleries therewith.

A branch connecion is then made with the casing pipe 3 for tapping thedischarge of pressure fluid, within the lowermost chamber 9a, using thefollowing technique. The outer casing 5, if present, is first cut awaythroughout the height of the chamber 9a, if this can be done withoutexcessively weakening the inner casing pipe against internal pressure.If not, additional concrete may have to be cast into the annular spacebetween the casings above and below the cut-away portion, or thesubsequent operations, described hereinafter, may have to be performedon the outer casing 5 rather than the inner casing 3. Assuming howeverthe inner casing 3 is found to be sufficiently strong to withstand theinternal pressure and the stress resulting from the operations tofollow, it is laid bare by cuting away both the outer casing 5 and thecement lining 6. If the wall of the inner casing 3 is deemed to be toothin or weak to withstand the subsequent operations it may be reinforcedlocally as required. A two-part sleeve or shell 10 is then fitted aroundthe casing 3. The shell 10 as shown in FIG. 2, has a cylindrical bodysubstantially larger in diameter than the outer diameter of the casing3, and has its ends tapered into flanges tightly surrounding saidcasing, and welded to the latter or otherwise secured in apressure-tight manner. A branch line 11 fitted with a flow control valve12 is passed through the gallery 9 and is connected in pressure-tightrelation with the side wall of shell 16} so as to communicate with theannular space between the shell and the casing 3. Also connected withthe sidewall of shell 10 is a drilling unit 13 which can be operatedfrom outside the shell lit) to drill a hole through the wall of casing 3and thereby establish communication from the interior of said casing tothe branch line 11 by Way of the annular space between the casing 3 andshell 1! Connecting with the drill housing 13 is a pipe 21 for theinjection of water, mud or cement under pressure into the casing throughthe drilling unit as will later appear. The details of the structurecomprising shell 10 and drill housing 13 will be described later withreference to FIGS. 2 and 3.

In each of the chambers 7a and 8a the inner well casing 3 is similarlylaid bare, and a sleeve or shell 17 and 18 respectively is securedaround it. The shells l7 and 18 are generally similar in shape to shell10, having a cylindrical body portion of larger diameter than the easing3, and inturned end portions welded around the casing surface. Theshells 17 and 18 are made of a grade of steel having substantialdeformability for reasons that will presently appear. Means are providedin each of the chambers 7a and 8a for applying high inwardly directedforces to diametrically opposite areas of the shell 17 or 18 so as toflatten the shell and therethrough the walls of casing 3, as indicatedin dotted lines in FIG. 1, thereby to pinch the casing and seal theinterior flow space therethrough. The pinching means may comprise a pairof hydraulic rams, not shown, having pusher heads 15 and 16 engaging theshell 17 or 18 at opposite points of each shell. The chamber 8a furthercontains a combined drilling and injection unit 13, which may be similarto the drill unit 13 provided in chamber 9a, but which is connecteddirectly with the wall of easing 3 just above the shell 18, instead ofbeing connected with the shell as was the case for unit 13 in. chamber9a. Unit 13' has a pipe 19 connecting with the body thereof forinjection of mud or cement therethrough and through the hole drilledthereby in the casing wall 3 into the interior of the casing, as will bepresently described.

The general procedure for stopping a blowout using the equipmentsummarily described above is the following. With the valve 12 in thebranch line 11 being initially closed, the combinationdrill-and-injector unit 13 is operated to drill a hole through thecasing 3 in chamber 90, and provide communication between the interiorof the casing and the annular space within shell 10. Valve 12 is thenopened, so that a substantial portion of the gas flow rushing up throughthe casing 3 is tapped off through pipe 11 and can be directedtherethrough to suitable storage tank means, and/or burned undercontrolled conditions in a flare. With the consequent reduction inpressure of the gaseous discharge through the well, the hydraulic ramdevice 16 can be operated to flatten the shell 18 and thereby pinch thecasing pipe 3 in chamber 8a, as indicated in dotted lines. Thecombination drill-and-injector 13 in chamber 8a is now operated to drilla hole through the casing wall just above the pinched portion, andimmediately thereafter inject a suitable amount of mud, cement or otherplugging material as indicated at 2% into the casing 3, by way of pipe19 and the body of the unit 13'. In many cases the residual leakage flowof gas through the pinched sect-ion of the well casing may be so greatas to prevent a successful plugging by means of the material at 20, asby causing injected cement to set in a porous condition. If this is thecase, then a single additional pinching of the casing 3 by means of ramdevice 15 in chamber 7a will in general be suflicient to correct thesituation. However, under especially severe circumstances, more than oneadditional points of the casing 3, spaced above the main pinched sectionin chamber 8a, may have to be subjected to a similar pinching treatment.Moreover an injector-drill device similar to 13' may be used inconjunction with the additional pinch section in chamber 7a (andpossibility at further additional points) for injecting pluggingmaterial thereat. On the other hand, there will be more practicalsituations where a single pinched and plugged portion of the casing 3,as in chamber 8a, will permit successful control of the blowout, so thateven the single additional tunnel 7, chamber 7a and associated equipmentwill not be needed.

At this stage the combustible gases are being discharged entirely by wayof branch pipe 11 and the blowout can be said to be under control. Thevalve 12 is gradually operated to seal off the branch line, andcompletely cut off the discharge of gas. The column of gas in the wellbelow the pinched section is now in static equilibrium, and pluggingmaterial, such as mud, cement and/or water, can be injected through pipe21 and the combination drill-andinjector unit 13 int-o the casing 3 toplug the casing somewhat below the branchoff point of pipe 11. Theplugging material should of course be selected so as not to interactobjectionably with the hydrocarbons present in the well. With the Wellplugged below the tapping 11, most of the valuable equipment present inthe chambers such as 9a, 8a, 7a can be dismantled and retrieved by wayof the galleries, the flattened and otherwise damaged portions of thepipe casing '3 cut away and replaced with new casing sections welded inplace, the concrete casing 6 and outer casing pipe 5 (if any) similarlyreplaced where they were removed, all of which operations are greatlyfacilitated by the provision of the working chambers 7a, 8a, 9a.Thereafter the plugs of material injected into the well casing by way ofthe injector drills such as 13 and 13 can be bored through from theground surface by conventional means, and the well can be rapidly putback into service to resume hydrocarbon-winning operations as before theblowout occurred. 'It will be noted in this respect that in contrastwith certain prior blowout controlling procedures which involve thedumping of enormous amounts of material into the oil or gas bed at thefoot of the well by means of an auxiliary drill hole, as earliermentioned herein, whereby the bed is liable to be contaminated to suchan extent that subsequent extraction from a wide area surrounding thewell where the blowout occurred will be permanently prohibited, themethod of the invention completely avoids this liability in that itinvolves dumping only limited amounts of plugging materials into thewell casing itself.

Certain components of the equipment summarily described above will now'be redescribed in greater detail with reference to FIGS. 2 to 5. Firstreferring to FIG. 2, it will be seen that the shell 10 serving to elfectthe branch connection or tapping in chamber 9a, is formed with an upperopening in its cylindrical side wall for connection with the branch line11, through a suitable welded and/or flanged joint. The shell 10 has atleast one further opening 10a formed in its side wall, four suchopenings being shown, and each surrounded by a welded-on flange 10b forthe attachment of injector drill unit 13. As shown in FIG. 3 theinjector drill unit comprises a cylindrical body or casing 13b having anend flange 13a adapted to be secured, e.g. bolted, over the flange 10bto provide a pressure-tight connection by way of an annular seal asshown. It will be understood that the flanges 10b of any openings 10a inthe shell 10 that are not in use, are sealed with suitable covers notshown. The drill body 131) is formed with. an axial through bore inwhich a drill shaft 22 is mounted for rotation in suitable bearings andby way of annular seals permits rotation of the shaft in apressure-tight manner. The shaft 22 is driven in rotation from anelectric motor 23 mounted beyond the outer end of drill casing 13 anddrivingly connected with the outer end of shaft 22 through a connectionnot shown. A conventional axial feed device 25 provided with a handwheelis associated with the outer end of shaft 22. The inner end of shaft 22projecting through the aperture 10a in shell 10 has formed or secured onit a drill tool or bit 24 of any suitable type, e.g. a diamondtrepanning bit or the like. The drill tool 24 is formed with an axialrecess 24a in alignment with an axial channel 22a formed through shaft22 over part of the length of the shaft, the outer end of channel 22abeing angled as at 2212 so as to open outwardly of said shaft into acylindrical groove 13c recessed in the drill housing around the shaft.The recess 13c corresponds in axial length with the axial displacementof drilling tool 24. Formed through a side wall of drill housing 13b isan inclined duct 21a which open into the recess 13c and is so positionedand angled as to register with the angled outer end portion 22b ofchannel 22a for a predetermined angular position of shaft 22 when saidshaft is axially retracted as in FIG. 3. Duct 21a connects with a unionprojecting from the side of drill housing 131) and fitted with aflow-control valve 26, which union is adapted for connection with pipe21 referred to earlier (see FIG. 1). Means are provided for blocking thedrill shaft 22 in the particular angular position thereof for which theouter end of its channel 22a registers with the duct 21a, and said meansinclude therein a tapered centering recess 22c formed in the outersurface of shaft 22 and a radial passage 13d formed through the sidewall of housing 131;. When the center recess 220 is positioned toregister with passage 13d, a centering pin 27 can be inserted throughpassage 13d to engage into the recess 22c, whereupon the shaft 22 isblocked in the aforementioned position in which the ducts 22b and 21aregister.

The injection pipe 21 and the associated flow passages provided in thedrill unit described may serve a dual purpose. During the drillingoperation, when motor 23 is energized to rotate the drill shaft 22 andbit 24 so as to form a hole through the well casing 3 as indicated at 14in FIG. 3, a liquid coolant and lubricant may be delivered by Way ofpipe 21 (at such time connected to a suitable pressure source ofcoolant) into recess 13c and thence through duct 22b22a-24a into thedrilling zone to cool the drill bit. The main function of the injectionarrangement described, however, is the subsequent injection of pluggingmaterial into the casing 3 as earlier described. After the hole 14 hasbeen drilled in the well casing, rotation of drill shaft 22 is arrestedand the drill shaft is retracted by means of the manual device 25 to therearward position shown in FIG. 3 wherein the drill bit 24 is abuttedagainst the end wall of drill body 1312, clearing the hole 14. The gasin well casing 3 now issues out through hole 14 into the annular spacewithin shell 10, and out through hole 100 and branch pipe 11. After thewell casing pipe has been scaled above the branch pipe connection inchambers 8a and 7a as described hereinabove, and cut-01f valve 12 hasbeen finally closed, the coolant delivery pipe is disconnected from thepassage 21a of the drill unit 13, and pipe 21, connecting with apressure source of plugging material, eg cement connected theretoinstead. Drill shaft 22 is rotated to the position in which centeringrecess 22c registers with passage 13d, and centering pin 27 is insertedto block the shaft in that position. A continuous flow passage is nowprovided for the heavy plugging material through pipe 21 and passages21a-22b22a24a14 into the Well casing 13 for sealing the well below thebranch connection as already explained.

Referring now to FIGS. 4 and 5, each of the shells 17 and 18 used in thewell-sealing operation in chambers 7a and 8a comprises as earlierindicated a shell in two parts welded to each other along theirlongitudinal edges and Welded around the casing at their ends. Onapplication of compression forces by means of the rams 15 and 16, theshell is deformed inwardly and the casing 3 is pinched, as indicated indotted lines in FIG. 4 and in cross section in FIG. 5. During thisoperation the wall of casing pipe 3, generally made of relativelybrittle carbon steel, will crack, especially at the edges 3a, 3b of theflattened section, and in the absence of the shells 17 and 18 of theinvention, there would be considerable leakage, through such cracks andthe pinching process would be ineffective. However, the shells 17 and 18according to the invention are made of a tough, relatively ductile gradeof steel and treated to present a high elongation characteristic. It isfound that in this way the leakage from the pinched well casing sectioncan be reduced to a negligible amount.

It will thus be seen that the steps of procedure and the appliancesdescribed provide the possibility of practically and eflicientlycontrolling dangerous blowout situations in oil and gas wells, with muchgreater reliability and at less cost than the more or less empiricalmethods currently used. The improved process moreover avoidscontaminating the bed of hydrocarbons being mined and permits ofresuming the extracting operations promptly after the blowout has beendealt with, through the same well and with only a small amount of repairwork. It will be evident that in view of the great variability ofindividual conditions that may be encountered, the practical details ofembodiment of the method and means of the invention may depart invarious ways from what has 6 been illustrated and described herein whilestill remaining within the scope of the invention as defined in theappended claims.

What we claim is:

1. In a process for controlling high-pressure fluid discharge frommetal-cased oil wells and the like, the steps of gaining access from aside of the well to a first point of the well casing below groundsurface and at least one further point below ground surface spaced abovethe first point; connecting a branch line to the well casing at saidfirst point to tap the fluid discharge therefrom; applying pressure toopposite sides of the well casing at said further point to deform thecasing to a substantially flattened condition; and injecting pluggingmaterial into the casing from a side thereof above the flattenedportion.

2. In a process for controlling high-pressure fluid discharge frommetal-cased oil wells and the like, the steps of gaining access from aside of the well to a first point of the well casing below groundsurface and at least one further point below ground surface spaced abovethe first point; connecting a branch line having valve means therein tothe well casing at said first point to tap the fluid dischargetherefrom; applying pressure to opposite sides of the well casing atsaid further point to flatten the casing thereat; injecting pluggingmaterial into the casing from a side thereof adjacent said further pointabove said flattened portion; operating said valve means to cut off theflow of fluid through the branch line; and injecting plugging materialinto the casing from a side thereof adjacent said first point below saidbranch line connection.

3. In a process for controlling blowout from a metalcased well, thesteps of gaining access from a side of the Well to a first point of thewell casing below ground level and at least one further point belowground level above the first point; connecting a branch line to the Wellcasing at said first point to tap the blowout fluid therefrom; sealinglysurrounding the Well casing at said further point with a shell made froma material having tough, ductile characteristics and applying pressureto opposite sides of said shell to flatten the shell and well casing toseal the well at said further point.

4. In a process for controlling blowout from a metalcased well, thesteps of gaining access from a side of the well to a first point of thewell below ground level and at least one further point below groundlevel spaced above the first point; sealingly surrounding the wellcasing at said first point with a shell having a branch line extendingtherefrom and dimensioned to define a sealed annular space between saidwell casing and shell; drilling a hole in said Well casing withing saidshell from the exterior thereof to connect the interior of the casingthrough said space with said branch line and tap blowout fluidtherefrom; and pinching the well casing to a flattened condition at saidfurther point.

References Cited by the Examiner UNITED STATES PATENTS 934,745 9/ 1909Joltok 1669 1,879,160 9/1932 Fowser 169-2 2,000,381 5/1935 Duffy 166902,482,687 9/1949 Mueller et a1 137-318 2,515,260 7/1950 Pichler 1373182,918,124 12/1959 Spearow 16621 OTHER REFERENCES Petroleum ProductionEngineering, by Uren, McGraW- Hill, 2nd edition pp. 444 and 445; 4thedition pp. 758 and 759, TN87OU7.

CHARLES E. OCONNELL, Primary Examiner.

C. D. JOHNSON, J. LEPPINK, Assistant Examiners.

1. IN A PROCESS FOR CONTROLLING HIGH-PRESSURE FLUID DISCHARGED FROMMETAL-CASED OIL WELLS AND THE LIKE, THE STEPS OF GAINING ACCESS FROM ASIDE OF THE WELL TO A FIRST POINT OF THE WELL CASING BELOW GROUNDSURFACE AND AT LEAST ONE FURTHER POINT BELOW GROUND SURFACE SPACED ABOVETHE FIRST POINT; CONNECTING A BRANCH LINE TO THE WELL CASING AT SAIDFIRST POINT TO TAP THE FLUID DISCHARGE THEREFROM; APPLYING PRESSURE TOOPPOSITE SIDES OF THE WELL CASING AT SAID FUTHER POINT TO DEFORM THECASING TO A SUBSTANTIALLY FLATTENED CONDITION; AND INJECTING PLUGGINGMATERIAL INTO THE CASING FROM A SIDE THEREOF ABOVE THE FLATTENEDPORTION.